The nurse on the telemetry unit is watching the electrocardiogram (ECG) monitor at the nurses' station when the alarm sounds. The nurse observes the client's ECG in the image. The nurse checks on the client and assesses that the client's status matches the rhythm on the monitor. What is the priority nursing action?

A. Call the health care provider for a change in cardiac drugs: Notifying the provider is important for ongoing management, but the rhythm shown in the image is ventricular fibrillation (VF), which is immediately life-threatening. Delaying action to call the provider risks the client’s survival. B. Place the client in a sitting position and administer oxygen: Positioning and oxygen may support a stable client with mild symptoms, but VF causes ineffective cardiac output, so interventions that only support oxygenation are insufficient. Immediate resuscitative measures are required. C. Call the rapid response team to come and assess the client: While the rapid response team can assist, VF requires immediate intervention—delaying defibrillation and CPR while waiting for others significantly reduces survival chances. D. Call a code and initiate cardiopulmonary resuscitation: Ventricular fibrillation is a pulseless, life-threatening arrhythmia that requires immediate activation of a code and initiation of CPR, followed by defibrillation. Early chest compressions and defibrillation are critical to restoring cardiac output and preventing sudden cardiac death.